Layers of the Earth

Sixth Grade Science Unit

Earth’s BeginningEarth’s BeginningEarth, the largest rocky planet, was formed

about 4.5 billion years ago. The Earth's interior is divided into four

different layers.It is cool on the surface but very hot deep

inside the planet. The center, or core, is as hot as 9000

degrees F which is hotter than the surface of the sun.

Earth’s InteriorEarth’s InteriorThe Earth's interior is made of rock and

metal. It has four main layers:

1) the inner core: a solid metal core 2) the outer core: a liquid molten core 3) the mantle: dense and mostly solid rock 4) the crust: thin rock material

Earth’s LayersEarth’s LayersHow are the

earth’s layers similar to an egg?

Shell=crustEgg white=mantleYolk=core

AsthenosphereAsthenosphere

LithosphereLithosphere

Lithosphere: where crust and top of mantle meet

Asthenosphere: The asthenosphere is a portion of the upper mantle just below the lithosphere that is involved in the plate movements.

LithosphereLithosphere

The Earth’s SurfaceThe Earth’s SurfaceThe Earth's surface is unique from the

other planets because it is the only one with liquid water.

Water helps to make surface features such as rivers, lakes and oceans.

The moving plates of the Earth’s surface form other surface features such as mountains, earthquakes and volcanoes.

Interior of the EarthInterior of the EarthMany geologists believe that as the Earth

cooled the heavier, denser materials sank to the center and the lighter materials rose to the top.

Because of this, the crust is made of the lightest materials (rock- BASALTS and granites) and the core consists of heavy metals (nickel and iron).

The CrustThe CrustThe outermost layer of the Earth is the crust. The crust is the layer that YOU live on, and it

is the most widely studied and understood.In the oceans, it is about 4 miles thick. On the thickest continents, it extends some

40 miles into the Earth.

The MantleThe MantleThe region just below the crust and

extending all the way down to the Earth's core is called the mantle.

The mantle is much hotter and has the ability to flow.

The convection current of the mantle is much like the convection current created in a pot of boiling water.

LithosphereLithosphere

AthenosphereAthenosphere

The CoreThe CoreBeneath the mantle is the Earth's core. The Earth's core consists of two layers:

The outer coreIt flows like a liquidMostly made of iron

and a solid inner core. It is VERY hot!It is in a solid state even though it is

hot enough to be melted. This is due to the enormous amount of pressure on it from the other layers that lie on top.

The Core The Core (continued)(continued)

The Outer and Inner Cores are hotter still with pressures so great that you would be squeezed into a ball smaller than a marble if you were able to go to the center of the Earth!

Because the outer core contains iron, when it flows it generates a magnetic field.

This is the source of the Earth's magnetic field.